Question

The passage of water-soluble substances through the plasma membrane is made possible by _________ in the membrane.

(a) channel proteins
(b) cholesterol molecules
(c) phospholipids
(d) glycoproteins

Answer 1

Channel proteins are responsible for the passage of water-soluble substances through the plasma membrane.

Step-by-step explanation:

The passage of water-soluble substances through the plasma membrane is made possible by channel proteins in the membrane. Channel proteins have hydrophilic domains that provide a hydrated opening through the membrane layers, allowing polar compounds to avoid the nonpolar central layer of the plasma membrane. Aquaporins, a type of channel protein, specifically allow water to pass through the membrane at a very high rate.